You can get it (regular, fossil diesel) from a regular gas station for your boat. The price, although probably cheaper than at the dock, includes tax (for roads, etc.), and so is probably not dyed. Otherwise, #2 diesel is #2 diesel.

You didn't say who manufactured your engine, but many manufacturers have issued statements on the use of various bio-diesel blends in their engines. Without clear guidance from the engine manufacturer, I would be reluctant to put a biodiesel (even B5) in my boat. The bio- vs fossil diesel discussion has been had many times on here and around the web.

I can't find a correct answer. I need to add some fuel to my tanks for winterizing. The boat is not able to get to a marina for fuel. So I was going to bring in some 5 gallon containers of diesel.

Can I just get it from a regular gas station or do I need to go a fuel dock? I know the gas stations have bio diesel, not sure if that is different from what is at the marinas?

Oh yeah, assuming I can use my gasoline 5 gallon, emptied, rinsed with water, and let dry. Thinking the ratio of diesel to whatever is in there is like 1000:1

You don't say where in the world you are, but assuming the USA, diesel found at gas stations is the same as diesel found at marinas. The difference is the price of diesel from a gas station includes road taxes that can be 20 cents per gallon or more. Diesel from a marina does not include taxes and is dyed red to indicate that it was sold for off road (including marine) use.

As for the portable jugs, empty them but do not rinse with water. A minute amount of gasoline will do far less harm than a minute amount of water.

I may be off base on this but I believe the diesel at the pump is ultra low sulfur diesel which has considerably reduced lubricity compared to the old style diesel that was just low sulfur and that is still served at the dock.
Having said that, I doubt that a low percentage of ULSD would make a significant difference for you next spring. I would be hesitant to go over 50% myself.
BTW, I also believe that gasoline at the dock does not contain Ethanol .....

There is no difference between diesel at the marina and diesel at the gas station . Also a bit of gasoline will not hurt the engine at all. Heck back in granddads day they used to mix about a 20% gasoline to diesel mix for the old farm tractors for winter use to protect from jelling.
With the newer ulsd I have not had an issue with jelling . However I have had to add something to improve lubricity .

Don't worry about the automotive diesel. Auto diesel is fine for your Yanmar. Yanmar marine engines are a very basic diesel engine compared to a TDI automotive engine. The older yanmar design is not quite as efficient, but is extremely forgiving when it comes to fuel. Your Yanmar can burn #1 or #2 diesel, on road, off road, or marine, and home heatingoil (basically #2 diesel). The difference with marine diesel (off road diesel) is no road tax and red dye. Off road diesel fuel is higher in sulfur than on road, has not been taxed the same, and cannot legally be used for cars and trucks on highways (although it works fine).

Boidiesel may not be the best in the cold and can be finicky when it comes to sludging so don't search it out to use it. Its not commonly found so don't worry about it.

Don't wash out your gas can unless it contains dirt. Some gasoline in the diesel is no problem (and some residual diesel in the can when you use it for gas again is also not a problem). In Europe owners commonly mix some gas in with the diesel in their cars for less gelling in very cold weather (illegal in the USA due to emissions).

How much fuel do you have left in your tank, and how often do you run your boat. If not alot and not much, you're probably better leaving the tank mostly empty for the winter. IMHO, old fuel is worse than a minute amount of moisture condensing in the fuel that's left. I'd throw some stabil and some biocide in there and put fresh fuel in it in the spring.

While the diesel you buy at the marina may not yet be ULSD, it will soon be. The EPA set a deadline of 2014 for all diesel fuels, including "off-road" to be transitioned to ULSD. In practice it will probably take awhile for this to trickle down to the marina supply, but it's hard to say.

So if the fuel is red, it no guarantee that it's not ULSD, just that it's fuel to be sold at the lower taxable rate.

If you're putting ULSD into your tank, what do you need to do? Be sure to add biocide, as ULSD is less inhibiting of microbial development. Consult your engine manufacturer regarding the advisibility of additives to increase lubricity of the lower sulfur fuel.

There is no difference between diesel at the marina and diesel at the gas station . Also a bit of gasoline will not hurt the engine at all. Heck back in granddads day they used to mix about a 20% gasoline to diesel mix for the old farm tractors for winter use to protect from jelling.
With the newer ulsd I have not had an issue with jelling . However I have had to add something to improve lubricity .

Not true, diesel at the pump also does not have any biocides included, the dye is used to identify taxed or un taxed fuel.
Fuel at the marinas is for marine use, and most marinas offer added constituents to protect marine engines.
You can add biocides to road fuel, as well cetane improvers.

How much fuel do you have left in your tank, and how often do you run your boat. If not alot and not much, you're probably better leaving the tank mostly empty for the winter. IMHO, old fuel is worse than a minute amount of moisture condensing in the fuel that's left. I'd throw some stabil and some biocide in there and put fresh fuel in it in the spring.

A full tank is not going to condensate, the previous years fuel will be fine for well into 2 years.

As mentioned, diesel at the fuel dock and diesel at the gas station are in most cases exactly the same thing. One might have dye added to show its tax status, but that's about it.

However, there are three considerations worth thinking about with biodiesel:
1. Does your engine mfg. approve of it? Most do, at least up to 8 or 10%, and it typically will not cause mechanical problems.
2. Biodiesel acts as an extreme detergent, and the introduction of bio into an older fuel system will cause the flushing of old sludge, deposits, tars, etc. into your filters. Be prepared to change filters several times to stay ahead of the accumulation.
3. Standard diesel fuel easily stores over a winter season with no loss of quality, but biodiesel, being a plant or animal product, deteriorates quickly and should not be stored over a winter season.

i have about 16 gallons out of a 26 gallon tank. Put in some stabil. Engine won't be started until next Mayish, I am in New England. I have always filled the tank as I have been taught not to leave any air to condense. But I am at a Marina this year that has no fuel service.

Not true, diesel at the pump also does not have any biocides included, the dye is used to identify taxed or un taxed fuel.
Fuel at the marinas is for marine use, and most marinas offer added constituents to protect marine engines.
You can add biocides to road fuel, as well cetane improvers.

Sent from SV Cloud Duster

The diesel that is at the gas station for cars and the off road diesel that is sold for heavy equipment and marine use is exactly the same except that the on road diesel is not dyed . They come from the same refinery and the same storage tanks. They add the dye when loading the fuel into the delivery truck. Any biocides that are added is done by the consumer. Not the manufacturer.

For the past 6 years I've been topping off after the haul out with the gas station bought diesel and adding stabil and biocide without any ill effects. The engine is an old Universal, very simple and probably does not know the difference whether the fuel is labeled "marine" or not.

Agree with posters who do not see any difference between gas station and marina bought diesel. Wish that the home heatingoil companies would sell diesel to boat owners directly. After all for many their boat IS their home. But we live in Orwellian times where ketchup is a vegetable and a liveaboard boat is not a home.